Sulphur Dioxide. Apa 
through innumerable small fissures sulphur is deposited, and the country 
rock is strongly impregnated with it. The amount of gas emitted is 
ordinarily not very great, but is increased enormously when the at- 
mospheric pressure is low. During periods of crater activity, paroxys- 
mal eruptions of gas and water are noticed near the center of the lake 
at intervals of from one to three hours, and whenever the bubbling 
begins, workmen row to the spot. By means of a pulley attached to a 
framework resting upon two boats, the men lower an iron bucket in the 
center of the bubbling area to the bottom of the lake. When the bucket 
is withdrawn it is practically filled with sulphur grains. In this man- 
ner, while the crater is active, a hundred buckets of sulphur are easily 
brought up in a day. This sulphur is for the most part dark grey in 
color and consists of oolitic grains. 
The process of sulphur deposition just described is not to be taken 
as typical, and Oinouye himself remarks’ that the production of sulphur 
in crater lakes is very unusual even in sulfatara sulphur fields. But 
this particular process illustrates strikingly the possibility of sulphur 
coming from sulphur dioxide. The fact that the water of Lake Ponto 
is charged with sulphur dioxide bears unmistakable evidence of the 
existence of this gas as a volcanic exhalation. Its reduction to elemen- 
tary sulphur can be assumed to take place through its interaction with 
carbon monoxide, which is very commonly found in volcanic exhalations 
together with other reducing gases. The freshly formed sulphur cools 
suddenly on coming in contact with the water in the lake and condenses 
in the form of oolitic grains. 
The theory set forth in this paper is not meant to displace other 
accepted theories on the origin of sulphur, but rather to supplement 
them. No one theory can explain the origin of the different deposits of 
sulphur; each deposit has to be dealt with separately, and it is hoped 
that some cases of sulphur deposition can be explained on the basis of 
this theory. 
The study of the origin of sulphur was undertaken at the suggestion 
of Dr. W. N. Logan of Indiana University, to whom my sincerest thanks 
are due. 
Since this note has been written an article by J. B. Ferguson 
appeared on “The Equilibrium Between Carbon Monoxide, Carbon Di- 
oxide, Sulphur Dioxide and Free Sulphur.”* Mr. Ferguson states that 
he undertook his work with the purpose to shed some light on the role 
of sulphur gases in volcanic activity. 
1 Loc. cit. 
2 Jour. Amer. Chem. Soc. 40, 1626 (1918). 
